/Engine/Source/Runtime/PerfCounters/Public/PerfCountersModule.h
all perf counters as they are stored, with minimum conversion
const [TMap](API\Runtime\Core\Containers\TMap)< [FString](API\Runtime\Core\Containers\FString), [FJsonVariant](API\Runtime\PerfCounters\IPerfCounters\FJsonVariant) > & GetAllCounters()